Nowadays, people usually backup their data, including photos or files, from the personal electronic devices, such as cell phones, to the cloud spaces. Sometimes it takes long time to back up all the data to the cloud spaces. If the cell phone is not being used by the human beings, the cell phone turns from the foreground mode to the background mode, and the application which is executed at the cell phone may stop executing when the cell phone turns to the background mode. That is, the cell phone may stop backing up data to the backup device when the cell phone turns to the background mode.